Primary melanotic schwannoma of the spinal canal.

A rare case of primitive melanotic schwannoma of the spinal canal associated with an angiomatous formation pushing against the spinal cord is reported. A study by immunohistochemistry and electron microscopy was performed. The positivity for S-100 protein, demonstrated by immunoperoxidase, could indicate that the tumor originates from the Schwann cell. The ultrastructural findings suggest that Schwann cells are capable of producing melanin. In our case the patient is alive and without evidence of the tumor 3 years after surgery. The existence of benign variants of melanotic tumors arising in the central nervous system is emphasized, based on this case and on those previously reported in the literature.